1. Field of the Invention
The present invention relates to thin film magnetic recording media such as a magnetic tape and a magnetic disk.
2. Description of the Prior Art
Recently, thin film magnetic recording media have attracted interest as high-density magnetic recording media and have gradually been put into practical use. It is well known that thin film magnetic recording media display remarkably excellent electromagnetic response properties in high-density magnetic recording operations as compared with the coating type magnetic recording media which have heretofore been employed. However, it is still necessary for thin film magnetic recording media to be improved in their practical properties for the purpose of their practical application as high-density magnetic recording media. The required improvements in the practical properties of thin film magnetic recording media may be roughly classified as follows:
(1) control of the surface configuration PA0 (2) improvements in the practical properties in terms of coating PA0 (3) improvements in quality of materials
Among these, the present invention is concerned with the control of the surface configuration of thin film magnetic recording media.
In high-density magnetic recording, losses in recording and reproducing operations as a result of spacing loss generally involve an extremely serious problem. For this reason, it is desired to improve the surface properties of thin film magnetic recording media. If the surface properties of thin film magnetic recording media are improved, however, although electromagnetic response properties are improved, runability and durability are impaired. Therefore, various surface configurations have been examined in order to improve the runability and durability as well as electromagnetic response properties.
The following is a description of a conventional thin film magnetic recording medium.
Referring to FIG. 1 which is a sectional view of a conventional thin film magnetic recording medium, the reference numeral 1 denotes a substrate, 2 each of the particles of a shape imparting substance, 3 a thin-film layer which includes at least a magnetic layer, and 4 projecting portions of the thin-film layer 3. It is possible by this arrangement to improve the electromagnetic response properties together with the runability and durability of a thin film magnetic recording medium by employing the substrate 1 which has relatively excellent surface properties and controlling the surface properties of the medium by the use of the shape imparting substance 2, as shown in FIG. 1. The above-described arrangement, however, suffers from the following problem. Namely, under a normal environment such as at 23.degree. C. and 50% RH, the electromagnetic response properties, runability and durability of the medium are all satisfactory, but under a harsh environment such as at 40.degree. and 95%RH, although the electromagnetic response properties and runability are still excellent, durability is not satisfactory.